Butylphthalide is a water insoluble oily compound with the following formula:

There are two optical isomers, levorotary and dextrorotary butylphthalide, due to the presence of a chiral carbon therein. Chinese patent application No. 98125618.X disclosed the use of levorotary butylphthalide in the preparation of pharmaceutical compositions for preventing thrombosis and platelet agglomeration. It was found that butylphthalide could regulate the function of NOS-NO-cGMP system and the metabolism of arachidonic acid in the neurocytes after ischemia. Chinese patent application No. 93117148.2 disclosed the use of racemic butylphthalide mixture in the preparation of pharmaceuticals for preventing and treating ischemia-induced diseases in mammals or human.
Butylphthalide can be obtained by extraction from natural celery seed oil or by chemical synthesis, as described in Chinese patent application No. 99109673.8 and the prior reference: Junshan Yang, Yalun Su, Chinese Pharmaceutical Bulletin, 1984, 31; 671, which realized the availability of butylphthalide.
The pharmaceutical formulations are required to release active agents quickly and exert therapeutic effects rapidly when they are used to treat ischemia-induced diseases or thrombosis. Usually, the formulations for treating acute disease are administrated by intravenous instillation. However, the butylphthalide can only be formulated into soft capsules for oral administration because of its oily characteristics. Therefore, solubility problem of the butylphthalide must be resolved firstly in order to obtain injectable dosage forms.
For the purpose of investigation of the clinical value of butylphthalide, the present applicant has filed a Chinese patent application titled “A inclusion complex of butylphthalide with cyclodextrin derivatives, a process for its preparation and the use thereof” on Jun. 18, 2001, in which solubility problem of butylphthalide was resolved. However, the levorotatory butylphthalide was not mentioned in that application.